3: Azithromycin-based extended spectrum antibiotic prophylaxis for non-elective cesarean delivery: a pragmatic multicenter placebo-controlled double-blind rct


      Standard antibiotic prophylaxis (AP) for Cesarean delivery (CD) does not cover some organisms such as Ureaplasmas, which are frequently associated with post-CD infections. We evaluated the effect of adding azithromycin (AZI) to usual AP on post-CD infections in women undergoing non-elective CD.

      Study Design

      The multicenter double-blind C/SOAP RCT ( NCT01235546), included women with singletons ≥24 wks’ GA who had CD during labor or at least 4 hrs after membrane rupture. All women received standard AP. Subjects were randomized to also receive either AZI (500mg in 250ml saline) or identical placebo (250ml saline) by a center-stratified computer-generated scheme. Study medication was given preferably up to 1 hr pre-incision (or as soon as possible after). The centrally adjudicated primary outcome was a composite of endometritis, wound infection, or other infection (abdominopelvic abscess, sepsis, pelvic septic thrombophlebitis, pyelonephritis, pneumonia or meningitis) within 6 wks. Secondary outcomes included neonatal morbidities and reported adverse events. We estimated that N=2000 would be needed to show a ≥33% reduction in the primary outcome from a baseline of 8-12% with 80% power and 2-sided alpha of 0.05. Analysis was by intent-to-treat.


      Of 17,790 women screened from 04/2011 to 11/2014, 2013 were randomized to AZI (n=1019) or placebo (n=994) at 14 sites. Groups were similar at baseline (35% Caucasian, 34% Black, 29% Latino and mean BMI of 29.9). Drug was administered before incision in 88% per group. The primary outcome occurred significantly less in the AZI group compared to placebo (Table; 6 vs 12%, p <.0001). Postpartum readmissions or emergency visits for any reason were also lower in the AZI group (Table). Neonatal outcomes were similar. Severe adverse maternal events (1.5% vs. 2.9%; p=.026) but not neonatal were less frequently reported with AZI.


      Adding AZI to usual AP for non-elective CD reduced post-CD infections (NNT=17) and severe adverse maternal events with no difference in neonatal outcomes.
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